Seal washers are a type of sealing component used in mechanical equipment and pipelines wherever fluid flow is present. They are made of metal or non-metallic sheet materials, cut, stamped, or trimmed into shape, and are used for sealing connections between pipes and for sealing connections between components of machinery and equipment. They can be categorized into metallic and non-metallic seal washers. The metallic types include copper washers, stainless steel washers, iron washers, aluminum washers, etc., while the non-metallic types include asbestos washers, non-asbestos washers, paper washers, rubber washers, and more.